Fan-cooled motor



Oct. 28, 1952 L. R. LUDWIG ETAL 2,615,937

FAN-COOLED MOTOR Original Filed Aug. 15, 1946 Fig.l.

WITNESSES: INVENTORS fifi'fiyj/ Leon R.Ludwig,Theodore C. Fockler,

7&0 A

BYQ 22 ATTORNEY William H.Formho|s and Howard T. Wolton.

Patented Oct. 28, 1952 UNITED STATES PATENT OFFICE FAN-COOLED MOTORPennsylvania Original application August 15, 1946, Serial No.

690,628, now Patent No. 2,571,907, dated October 16, 1951. Divided andthis application February 28, 1951, Serial No. 213,091

8 Claims. 1

Thisiis-ta division of our application Serial No. 690,628, filed August15, 1946, now Patent No. 2,571,907, .issued October 16, 1951, onsplashproof motors.

Our present invention relates to electric motors, and more particularlyto a redesigned line of induction motors, which have the advantages ofextreme simplicity and economy of construction, a pleasing appearance, asmall size, within the standardization-limits established by theindustry, and complete convertibility into a maximum number ofmotor-types with a minimum number of parts.

A principal object of our invention is to provide anovel type offan-cooled motor, in which each bracket has only an axial register, andnot a radial register, with the stator-core, so as to provide a .totallyenclosed motor-construction, while the necessary radial register, foraligning the bearings carried by the brackets, is provided by anintermittent register with a prepared machined surface on the respectiveends of a cylindrical frame-ring. Among other advantages, this form ofconstruction makes possible the use of a core-holding end-plate which isonly a quarter of an inch thick, or less, or, in general, thin enough sothat it can be punched, as distinguished from a cast or machined job.

With the foregoing and other objects in view, our invention consists inthe structures, combinations, systems, methods and parts, hereinafterdescribed and claimed, and illustrated in the accompanying drawings,wherein:

Fig. .l is a longitudinal sectional view of a form of embodiment of ourinvention, to provide a fan-cooled motor, the motor-foot being shown inelevation, and

Fig. 2 is an end view of the motor shown in Fig. l, with the top half ofthe bracket cut away.

All forms of embodiment of our motor utilize a stator-member comprisinga strong, rigid, frame-ring I and a stator-core assembly 3. In manycases, it is desirable that the frame-ring l shallconstitute animperforate enclosure-ring for the machine. The stator-core assembly '8comprises a rigidly held stack of stator-laminations 9,, which have atight fit, known as an interference-fit, within the inside of theframe-ring l, at a plurality of circumferentially-spaced points, asindicated at in Fig. 2. It is preferable that the stator-laminationsshall fit tightly enough, in the frame-ring 1'1,v so as to readilyconduct heat .irom the laminations to the frame-ring. At

other points around their peripheries, the statorlaminations 9 :arespaced .from'the inside of the frame-ring i, so-as to provide taxiallyextending ventilating-spaces H, which admit of an .axial air-flow overthe stator-core laminations S, preferably, though not necessarily,extending from one end of the core straight through to the other end.The stator-core laminations carry the stator or primary windings II],the end-turns or which are shown in Fig. 1.

Thestack of stator-core laminations 9 may be held together in anydesired way, so far as the broader aspects of our invention areconcerned. We prefer to use the improved core-holding assembly whichconstitutes the subject-matter of Patent No. 2,447,645, granted August24, 1948, to Arthur E. Goodwin and Leon R. Ludwig. It is sufficient tosay that the stator-laminations '9 are held between two end-plates 13,which are held tightly compressed against the laminations, by means of aplurality of circumferentially-spaced, elongated, axially disposedlamination-holding members, which are shown as locking-bars I4. Theend-plates '13 do not make a tight fit with the inside of the frame-ringl, but are welded 'to the inside of the frame-ring, after thecore-member is assembled in the ring, at a plurality ofcircumferentially spaced points, as indicated at IS in Fig. 2. Theremaining peripheral portions of the end-plates are spaced from theinside of the frame-ring l, to provide the aforementioned axialventilating spaces ll.

After the stator-frame has been assembled, as above described, two fitsare machined on each end of the frame, these four machining operationsbeing advantageously performed simultaneously. One of these fits is inthe frame-ring I, both ends of which are rabbeted, to provide anaccurate radial-register surface 15, and an accurate axial-registersurface [1. The other fit is on the stator end-plates 13, the exposedendfaces of each of which are machined, to provide an accurateaxial-register surface 18, as shown in Fig. 1.

In our fan-cooled machine, as shown in Fig. 1, use is made of themachined, axial-register surfaces IS on the end-plates !3 of thestator-core assembly. These axial-register surfaces l8 c0- operate withaxial-register surfaces 43 on the peripheries of two imperforatebrackets 44, one on each end of the machine. These im-perforate brackets44 are provided with bearings 23 for supporting the rotor-shaft 2 1. Inthe particular motor which is shown in the drawings, the bearings 23 areball-bearings, in which the statorpart 25 of the bearing is permanentlyassembled with the rotating'b'earingepart '26 which is fixedto, or

carried by, the shaft 24, so that the shaftmounted bearing-part 26 hasto be pressed on or off the shaft, whenever a bracket 25 is applied to,or removed from, the machine, or, if the ballbearing part 26 is leftattached to the shaft, then the stationary bearing-part 25 has to bemoved in or out of the bearing housing 23, when the bracket is appliedto, or removed from, the machine. At any rate, the two rotatingbearingparts 25, at the two ends of the machine, are at a fixed distanceapart, said distance being fixed by the particular shaft 24 which isutilized.

The motor which is shown in Figs. 1 and 2 is completed by a rotor-memberwhich is carried by the motor-shaft 24. The rotor is characterized by arotor core-member 253, and suitable fan means for ventilating themachine. In the particular form of motor which is illustrated, a castsquirrel-cage rotor is utilized, having endrings which are shown at 30,and a plurality of straight, or axially directed, ventilating-vanes 32',projecting axially from each of the endrings 30.

The outer peripheries of the imperforate brackets 44 make no radialregister with the statorto the respective ends of the stator-member, by

means of bolts 22' which pass through the lugs 45 and into the ends ofthe respective lockingbars 14. The lugs 45 are provided with accurateradial-register surfaces 46, which register with the correspondingradial-register surface It of the end of the frame-ring l, but theselugs have no axial-register with the frame-ring.

It will be noted that the two imperforate brackets 44 of Fig. 1 make acontinuous axialregister fit, but no radial-register fit, with therespective ends of the stator-core assembly, while the peripheral lugs45 on the two imperforate brackets 44 make an intermittentradial-register fit, but no axial-register fit, with the respective endsof the frame-ring 1. The continuous axialregister fits, at the surfacesI 8 and 43, provide closed-housing joints between the stator-core andthe two imperforate brackets 44. The fact that the brackets 44 areimperforate, or have no ventilating-hole therein, added to the provisionof the closed-housing joints I 8--42, results in the complete enclosureof the motor, as shown in Fig. 1. The primary end-turns l are ventilatedby the internally mounted fan-vanes 52' which are inside of the machine.These fan-vanes or blades 32' operate by stirring the air within each ofthe imperforate brackets 44. They do not produce an axially flowingstream of ventilatingair, because the outer periphery of the statorcore9 is effectually sealed, at l843, at both ends of the stator-core.

In the fan-cooled, totally enclosed machine of Fig. 1, an externallymounted fan-means is provided, in the form of one or more axial-flowfans 48, only one being shown, which is removably mounted on the shaft24 on the outside of at least one of the bearings 23, for causing air toflow from one end of the machine to the other, this axial air-flow beingdirected by means of two identical hoods 50, one at each end of themachine. Each hood 50 has a peripheral part having an accuratelymachined, axial-register surface which registers or fits against thecorresponding surface H at that end of the frame ring I, so as to make asubstantially continuous fit on that end of the frame-ring. The hoods 50may be retained in place by any suitable means, such as the set-screws42. The two hoods 50 are provided with air-vent openings 52 which arepreferably disposed somewhere near the bearings 23, so as to constrainthe external ventilating-air to pass over the bearings, as shown by thearrows 39'. The air-vents 52 are also preferably on the bottom halves ofthe hoods 54, for protection against the entry of water and dirt.

In operation, it will be noted that we extract heat from the primaryend-windings ill, by internal ventilation, and also use an axially flowing stream of air which passes through the axial ventilating-space I lbetween the outer periphery of the stator-laminations 9 and the insideof the frame-ring I. This axially directed stream, in the fan-cooleddesign of Fig. 1, is an external stream 39' which also cools theimperforate or total-enclosure brackets 44, which thus cools theinternal air trapped within the enclosed machine, while at the same timecooling the frame-ring I, which is in direct heat-radiating contact witha plurality of spaced points l0 around the circumference of thestator-laminations, in the manner shown in Fig. 2.

While we have shown our invention in forms of embodiment which are atpresent preferred, we desire it to be understood that our invention issusceptible of a wide variety of application and adaptation. We desiretherefore, that our claims shall be accorded the broadest constructionconsistent with their language.

We claim as our invention:

1. A fan-cooled dynamo-electric machine com prising a strong, rigidframe-ring having an accurate radial-register surface at each endthereof, a stator-core comprising a rigidly held stack ofstator-laminations fitting, at a plurality of spaced points about theouter periphery of the stator-laminations, within the inside of 'theframe-ring, the stator-laminations being spaced from the inside of theframe-ring at other peripheral points, the stator-core having anaccurate axial-register surface at each end thereof, a stator-windingcarried by the stator-core, two imperforate brackets removably mountedon the frame-ring, one at each end, each imperforate bracket having noventilating-hole therein and having an accurate peripheralaxial-register sur face fitting against the corresponding axial-registersurface of the stator-core, said imperforate brackets having no radialregister with the stator core but having peripheral lugs havingradialregister surfaces having an intermittent radial register with therespective radial-register surfaces of the frame-ring, bearings carriedby said imperforate brackets, a rotor-member having a shaft which issupported by said bearings and having internally mounted fan-means forat least ventilating the end-turns of the stator-winding at both ends ofthe stator-core, said rotor-member further having externally mountedfan-means, removably mounted on the shaft on the outside of at least oneof the bearings, for causing a ventilating gas to flow axially Withinthe space between the inside of the frame-ring and the periphery of thestator-laminations, and two hoods, each havinga ventilating-hole andhaving a peripheral part which makes a substantially continuous fit atits end of the frame-ring.

2. A fan-cooled dynamo-electric machine comprising a solid frame-ring, astator-coremember supported by said frame-ring, said statorcore engagingthe frame-ring at spaced points other portions of the outer periphery ofthe stator-core and the frame-ring, thus d'efining an axially extendingventilating-space which admits of an axial air-flow over the stator-coreframone end of the core t'o'the other, "ashaft, a rotor-core membercarried by the shaft, 'two imperforate brackets removably mounted ontheframe-ring, one at each endf-said brackets engaging the frame-ring atcircumferentially spaced points, each imperforate bracket having noair-hole therein, and having a bearing for supporting the shaft at thatend of the machine, further having a peripheral part having a continuousaxial register with its end of the stator-core member, axial-flowfan-means, removably mounted on the shaft on the outside of at least oneof the bearings, for causing air to flow from one end of the machine tothe other, and two hoods each having a centrally disposed air-hole and aperipheral part which makes a continuous fit on its end of theframering.

3. A fan-cooled dynamo-electric machine comprising a solid frame-ring, astator-core member supported by said frame-ring, said stator-coreengaging the frame-ring at spaced points about its periphery, withradial spaces between other portions of the outer periphery of thestator-core and the frame-ring, thus defining an axially extendingventilating-space which admits of an axial air-flow over the statorcorefrom one end of the core to the other, a shaft, a rotor-core membercarried by the shaft, two imperforate brackets removably mounted on thefame-ring, one at each end, each imperforate bracket having no air-holetherein, and having a bearing for supporting the shaft at that end ofthe machine, and further having a peripheral part having a continuousaxial register but no radial register with its end of the stator-coremember, and further having an intermittent radial register with its endof the frame-ring, axial-flow fan-means, removably mounted on the shafton the outside of at least one of the bearings, for causing air to flowfrom one end of the machine to the other, and two hoods each having acentrally disposed air-hole and a peripheral part which makes acontinuous fit on its end of the frame-ring.

4. A fan-cooled dynamo-electric machine comprising a solid frame-ring,an end-plate secured within the inner periphery of the frame-ring neareach end of the frame-ring, a stator-core member secured between the twoend-plates, said stator-core engaging the frame-ring at spaced pointsabout its periphery and the intervening portions of the outer peripheryof the stator-core being radially spaced from the inner periphery of theframe-ring, the end-plates having airwents theret-hrough, admitting ofan axial air-flow over the stator-core from one end of the core to theother, a shaft, a rotor-core member carried by the shaft, twoimperforate brackets removably mounted on the frame-ring, one at eachend, each imperforate bracket having no air-hole therein, and having abearing for supporting the shaft at that end of the machine,-

and further having a peripheral part having a continuous axial registerbut no radial register with its end-plate, and further having anintermittent radial register with its end of the frame-ring, axial-flowfan-means, removably mounted on the shaft on the outside of at least oneof the bearings, for causing air to flow from one end of "the machine'tofthe other, and two hoods each having a centrally disposed'air-hnleanda peripheral part which makes a continuous fit on its "end of theframering.

5. A totally enclosed dynamo-electric machine comprising a strong, rigidsolid frame-ring'having an "accurate radial reg'ister surface at eachend thereof, '-a stator-core comprising "a rigidly held 'stackof'stator-laminations fitting, at a plurality of spaced points about theouter periphcry of the 'stator-laminations, within the inside of theframe-ring, the stator-'laminations being spacedfrom'theinside of theframe-ring at other peripheral .points, the stator-core having anaccurate axial-registersurface at each end thereof, astator-'winding'carried by the stator-core, two imperforate bracketsremovably mounted on the frame-ring, one at each end, each imperforatebracket having no ventilating-hole therein and having an accurateperipheral axial-register surface fitting against the correspondingaxialregister surface of the stator-core, said imperforate bracketshaving no radial register with the stator-core but having peripherallugs having radial-register surfaces having an intermittent radialregister with the respective radial-register surfaces of the frame-ring,bearings carried by said imperforate brackets, and a rotor-member havinga shaft which is supported by said bearings and having internallymounted fan-means for at least ventilating the end-turns of thestator-winding at both ends of the stator core.

6. A totally enclosed dynamo-electric machine comprising a solidframe-ring, a stator-core member supported by said frame-ring, saidstator-core engaging the frame-ring at spaced points about its peripherywith radial spaces between the intervening portions of the outerperiphery of the stator-core and the frame-ring, a shaft, a rotor-coremember carried by the shaft, and two imperforate brackets removablymounted on the frame-ring, one at each end, said brackets engaging theframe-ring at circumferentially spaced points, each imperforate brackethaving no air-hole therein, and having a bearing for supporting theshaft at that end of the machine, and further having a peripheral parthaving a continuous axial register with its end of the stator-coremember.

'7. A totally enclosed dynamo-electric machine comprising a solidframe-ring, a stator-core member supported by said frame-ring, saidstator-core engaging the frame-ring at spaced points about its peripherywith radial spaces between the intervening portions of the outerperiphery of the stator-core and the frame-ring, a shaft, a rotor-coremember carried by the shaft. and two imperforate brackets removablymounted on the frame-ring, one at each end, each imperforate brackethaving no air-hole therein. and having a bearing for supporting theshaft at that end of the machine, and further having a peripheral parthaving a continuous axial register but no radial register with its endof the stator-core member, and further having an intermittent radialregister with its end of the frame-ring.

8. A totally enclosed dynamo-electric machine comprising a solidframe-ring, an end-plate secured within the inner periphery of theframering near each end of the frame-ring, a statorcore member securedbetween the two endplates, said stator-core engaging the frame-ring atspaced points about its periphery and the intervening portions of theouter periphery of the stator-core being radially spaced from the in- 8REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Number Name Date Ansingh Aug. 7, 1934Mendenhall May 28, 1935 FOREIGN PATENTS Country Date Australia Oct. 26,1945

